


Behemoth

by seths_dream



Category: Final Fantasy XV
Genre: Casual Sex, First Time, Hand Jobs, Hints of other chocobro pairings, M/M, Oral Sex, Plot What Plot/Porn Without Plot, Size Kink, Virgin Prompto Argentum
Language: English
Status: Completed
Published: 2020-10-07
Updated: 2020-10-07
Packaged: 2021-03-07 18:21:11
Rating: Mature
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,997
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/26872075
Author URL: https://archiveofourown.org/users/seths_dream/pseuds/seths_dream
Summary: Gladio’s a big guy, yeah. It’s a fact of life. Grass is green, chocobos are a gift to humanity, and Gladio is huge.Except it’s one thing to know it, and another thing tofeelit.
Relationships: Gladiolus Amicitia/Prompto Argentum
Comments: 4
Kudos: 68





	Behemoth

**Author's Note:**

  * For [quiteuneventful](https://archiveofourown.org/users/quiteuneventful/gifts).



> Happy belated birthday for my baby cherub Quite!! Thank you for being patient with me while I wrangle my poor laptop. Have something quick and dirty. ;D You asked for size kink, so of COURSE it had to be about Gladio. I hope you enjoy! ♥♥♥

Traveling around an entire continent with his three closest friends, Prompto got used to a few things real quickly: Showers and mattresses are sent by the Astrals; rock-paper-scissors lays down the law and god forbid you try to argue against the results; the best way to ply Noct out of bed is to waft the smell of breakfast under his nose; and Gladio takes up more space than you’d think. Gladio is _big._ Tall, broad, muscular as hell with a big personality to match. He takes up two-Prompto’s worth of space in the tent, the Regalia, the motel beds (and eats two-Prompto’s worth of Iggy’s cooking, too). When Prompto stepped into a caravan for the first time, he thought it was cramped… and then Gladio ducked inside, and he realized a whole _new_ meaning of how cramped a room could be.

And yeah, Prompto gets caught up in admiring Gladio’s muscles from time to time. Who doesn’t? He catches Noct and Ignis doing the same, not to mention passersby in Lestallum and rest stops. They’re admirable muscles, okay? Prompto finds it hard to keep his eyes to himself.

And he’s not objectifying Gladio, not really. Prompto appreciates him for a lot of things. He’s a bit of a jerk, but in a fun way. He’s matter of fact and doesn’t give out false compliments, which makes his “Nice shot, Prompto”s _extra_ special. He’s also just… noticeable, physically. 

Gladio’s a big guy, yeah. It’s a fact of life. Grass is green, chocobos are a gift to humanity, and Gladio is huge.

Except it’s one thing to know it, and another thing to _feel_ it.

Skin to skin, Gladio is absolutely _massive._

They ended up like this, somehow--a golden afternoon with Iggy and Noct out gathering firewood, a stolen look or two in the tent that ended up being not _quite_ so stolen… and now they’re on each other. Prompto’s kissing him, sitting on his lap, cradled in muscular arms, and he realizes Gladio could pull tighter and choke him between those rock hard biceps. Gladio could pin him like a fly while barely exerting effort.

Prompto kinda wants him to.

Gladio’s being gentle, though, in a way Prompto never expected he would be. Big, gruff Gladiolus Amicitia kisses like the male protagonists in the chick flicks Prompto would drag Noctis to watch back in Insomnia, when they’d get Ignis to drop them off at the movie theater to celebrate the end of exams. He shouldn’t be surprised after seeing the trashy novels Gladio reads in the Regalia.

It feels nice. It feels good, _great_ even, but…

Even while Prompto is sucking on Gladio’s tongue and just about purring at the feel of Gladio’s fingers carding through his hair, he sort of wants _more._ He’s had more than a few late-night fantasies of Gladio taking him apart, and yeah, he’s not complaining about this seriously fantastic experience, but he can’t help but want to feel Gladio take him over. 

Gladio pulls back just a little, and resists when Prompto tries to tug him right back in, because he can’t get enough of that _mouth_. “I can hear you thinking. What’s up? This all okay?”

“Actually, uh…” It’s embarrassing to say, and Prompto almost doesn’t say it, but he catches the worry in Gladio’s expression and rushes to reassure him. “It’s more than okay, seriously, dude, it’s… it’s incredible. I just, uh. Could you maybe. Like. Hold me down?”

 _That_ gets a slow, big smile out of Gladio. “Well, well, well, didn’t think you had that in you, blondie,” he practically purrs. “I should’ve guessed you’d be a bit of a masochist.” 

Prompto doesn’t know what he means by that--does he give off masochist vibes without realizing it? Do all of them think that? Shit, is it true?--but he can’t get any more words out because Gladio picks him up and maneuvers him over to the sleeping bag, moving Prompto like he weighs nothing, and that just gets Prompto even hotter. “Anyone ever tell you how freaking hot it is that you can do that?” he gasps out, struggling against Gladio’s hold just to prove to himself that he _can’t_ break free.

Gladio snorts. “Constantly.”

Then he’s stripping Prompto, lifting his hips for him and wrangling him out of his clothes. Prompto doesn’t even have time to feel awkward about his body, because Gladio’s stripping off his own shirt then, and there’s no way Prompto can hold a thought other than _oh, shit, he’s hot._

Gladio has more muscles than Prompto’s ever seen, and he knows they aren’t just for show. Just two days ago he’d _suplexed_ a _voretooth._ It was incredibly distracting, and Prompto ended up needing a potion after that fight.

“You ready to see what else is big?” Gladio hooks his fingers in his underwear.

Prompto doesn’t want to ruin the mood, but he can’t stop himself. He bursts out laughing. Gladio’s eyes crinkle back at him and he pulls his underwear down.

Prompto stops laughing. That… yeah, that’s big. Big like those porn star dicks he always thought _had_ to be fake, and maybe they were, but this is…

“Damn, big guy,” Prompto breathes, and he can’t stop himself from wrapping a hand around the thick length. He hears Gladio suck in a breath, but he’s too busy watching the cock in his hand to look up at his expression.

He can’t stop himself; he slides down Gladio’s long, long body and flicks his tongue tentatively against the red, engorged tip, watches it twitch and fill out even more. He’s never seen a dick so up close and personal, and he’s mesmerized.

“Prompto, get back up here, damn you,” Gladio growls, and grabs Prompto by the armpits to hoist him back up effortlessly. “I’m not done touching you.” He smirks a little once they’re face to face again. “Not that I blame you for getting distracted.”

“You’re an ass,” Prompto says, but his voice leaves him in a whine when Gladio trails a hand down his chest, tweaks at his nipples with roughly-callused fingertips, then cradles his cock in his fist.

If Prompto didn’t know his cock like the back of his own hand--a perfectly average sized cock, thank you very much--he would think he’s _small,_ the way it’s dwarfed in Gladio’s fist. His head just barely peeks out from Gladio’s fingers, and Gladio slides his thumb over that head without moving his hand an inch. Fuck, that’s hot. 

At a pointed nudge, Prompto slides off Gladio and onto his back so Gladio can cover his body with his own, propping himself up with one elbow and watching Prompto’s face intently. Prompto squirms. Gladio’s consuming him so entirely, barely having to move his fist with each stroke, his whole body lain out over Prompto’s so that Prompto is sure if someone came into the tent, they wouldn’t even _see_ Prompto was there at all… This is everything Prompto could have wanted, and the fact that he’s _getting_ it? He can’t believe how lucky he is right now. He wants to pinch himself, but he figures the pinches Gladio gave his nipples were good enough, right?

"Feels good," Prompto manages to say, encouraging Gladio. He bites his lip briefly at another swipe of Gladio’s thumb along his slit. 

"Does it, now?" So close to him, Prompto can _feel_ the vibration of Gladio's low voice in his chest more than he can hear it. "I'll keep that up, then." Gladio curls his hand a little firmer, almost too firm, but hell if it still doesn’t feel way too freaking good. Prompto feels like his brain is melting from his ears.

"Okay, um, okay d-dude, I'm getting close..." Prompto bites his lip harder and squeezes his eyes shut against the amused expression he’s sure Gladio is making. Look at pathetic virgin Prompto, coming after barely three minutes of sex. He feels a tear prick at one of his eyes--from pleasure, he’s telling himself, not from self-inflicted humiliation. 

Except Gladio's hand leaves his cock to cup his face, inadvertently smearing a bit of pre-come on his cheek, and Prompto blinks his eyes open to find Gladio looking at him. His eyes are fond, not mocking, but there’s a hint of a frown at the tight edges of his mouth. "Hey, Prompto. It's okay to let go. That's what we're here for, yeah? Let me take care of you."

And _those_ words send a shiver down Prompto's whole body. He gulps, nods a little too quickly and almost hits his head on Gladio’s chin. "Y-yeah. Roger, captain." He forces his body to relax back onto the sleeping bag and reminds himself it’s _okay._ Gladio wants to do this to him. He isn’t entirely sure _why,_ but he’ll take it. 

Gladio's hand is back on his cock then, and Prompto’s grateful for the short reprieve he got because he isn’t on the edge anymore. Gladio said it was fine, yeah, but Prompto wants it to last. He’s not ready for this real-life fantasy to be over yet, even if he’s _pretty_ sure this’ll be a repeat experience. Gladio seems the fuck buddy type, and Prompto is far from complaining. 

Gladio’s strokes are just as mind-numbingly good as before, though, so it’s barely any longer before Prompto is riding that edge again. Gladio leans his weight more heavily on his elbow so he can take his free hand and pull Prompto’s bottom lip, freeing it from his teeth. Prompto didn’t even notice he was biting at it again. “Don’t hold back,” Gladio’s growl vibrates into his ear, and Prompto’s hips buck upwards at how that sounds, at how that _feels._ He feels Gladio’s hard cock as he does, and that winds him up tighter, and his gasps are coming out unfiltered now that he’s making an effort not to hold them back. 

“Come on.” Prompto opens his eyes to see Gladio smiling devilishly at him. A bead of sweat drips from Gladio’s hair onto Prompto’s face, and it’s a little gross, but he can’t bring himself to really care. “Come on, I can tell you’re close… you’re shaking just for me, aren’t you?”

Prompto whimpers in agreement, and then Gladio dips in to kiss him and fist _faster,_ and his weight presses into Prompto almost enough that he can’t breathe, and that’s it, Prompto’s gone, he’s curling up, coming hard and yelling in anguished pleasure. 

Prompto falls back, splayed on the sleeping bag, and tries to recuperate and get his breathing under control. When he looks up, Gladio looks _incredibly_ smug. “Blew your mind, huh?” 

Prompto’s mind is a little too addled to come up with a witty retort right away, and the process is _completely_ aborted when Gladio brings his messy hand to his lips and licks away Prompto’s come. He makes a considering face and says, “Guess you’ve been eating your fruits and veggies.”

Prompto rolls his eyes, and an intrusive thought flicks to his mind: _wonder if Noct’s come tastes bad then…_ He freezes and looks at Gladio, and can tell Gladio had the exact same thought by the expression on his face. Prompto snorts, and then they break the sensual mood because they both end up laughing a little.

(Prompto doesn’t know what it says about him that he still finds the idea of swallowing Noct’s come _incredibly_ appealing. He guesses Noct’s pretty face probably still makes up for it.)

Prompto’s thoughts catch up to his post-orgasm mind, though, and he finally gets out, “Blew my mind? I don’t think so, big guy. I’m about to blow _yours."_ He sits up and tries to push at Gladio’s shoulder, which goes absolutely nowhere. Gladio is a brick wall, and damn, it’s as annoying as it is hot. 

“Lie down,” Prompto almost whines, and Gladio grins as he lies back. 

“Just wanted you to use your words like a big boy,” Gladio says as he pillows his arms behind his head. The position makes his biceps bulge more, and Gladio snorts again when Prompto spends a few seconds unable to tear his eyes away. 

Still, he manages to make his way down Gladio’s glorious body without too many detours (his muscles are just so _lickable,_ okay? How is it possible to have this many abs, anyway?), and his mouth waters embarrassingly once he’s level with Gladio’s cock. “Don’t pull me away this time,” he mumbles before licking around the head again.

Gladio doesn’t. Instead, his thigh muscles shift and relax under Prompto’s hands as Prompto licks along the sides of his cock. He spends a good amount of time getting Gladio’s dick nice and wet to smooth the way for his lips. He isn’t sure yet how far he can get his mouth around this thing--he honestly doesn’t think he’ll be able to take that much, but he wants to try. 

He wraps his mouth around the tip then and sinks down, down, d--okay, that’s too far down. He pulls back and coughs. Gladio’s thumb wipes at his chin, cleaning up some of the spit there, and Prompto looks up into his warm gaze.

“Don’t push yourself. I know it’s a lot. Most people can’t get far down.” His tone is matter-of-fact even while his words are a little smug. “Just take what you can, and use your hand for most of it.”

Prompto wants to grumble--he wants to prove he can do it, wants to prove he can be _better_ than the others, wants to have the dick sucking skill of a _god_ (because only a god could deepthroat Gladio, probably)--but he acquiesces. He wraps his hand around Gladio’s cock before sliding his mouth onto it, and the space between his hand and mouth is _still_ too much to take.

He pushes a little further, feels the back of his throat massage Gladio’s cock, and darts a look upwards. Gladio’s face is tipped back so Prompto can’t see it, but he can feel his thigh muscles trembling, and his chest looks flushed. Prompto takes a chance and forces his head a little further--and then chokes and pulls back again.

“For fuck’s sake--” Gladio half-sits up and glares down at Prompto. Prompto feels properly chastised. “Just do what I said, you little brat. I’m not going to let you hurt yourself on my dick.”

Prompto huffs. “Okay, okay, geez, I promise I won’t, like, kill myself on dick. Though if I _had_ to go, that would be…” He catches Gladio’s unamused expression. “Okay, got it, I’ll… I’ll be careful.”

This time, when he moves back down to take Gladio in his mouth, Gladio keeps himself propped up. Prompto can practically feel his eyes on him, but he keeps his own downcast. All the blowjob porn he’s watched showed intense eye contact, but it feels way too intimate and awkward to try for that. Instead, Prompto concentrates on making Gladio feel as good as possible with his tongue and his hand. 

And Gladio’s _definitely_ feeling good, if the rumbling groans he’s making are any indication. Prompto feels a little proud, and redoubles his efforts, though he makes sure not to go too far down on Gladio’s cock again. He uses his tongue, instead, rubbing it hard against the underside and learning what makes Gladio pant, learns how much pressure to use with his hand and how Gladio doesn’t react when he licks into his slit, but he _really_ reacts if Prompto runs his tongue along the ridge of his head. Not bad for his first blowjob. 

“Damn, you’re doing so good,” Gladio murmurs, sending a jet of heat through Prompto. It’s too soon for Prompto to get hard again, but he feels _good_ doing this, better than he’d thought. He likes that he’s good at it, and a drop of precome squeezes from the tip of Gladio’s cock as his pants grow louder.

Prompto darts his eyes upwards again to see Gladio’s head tilted back again, the tendons of his neck standing out. “Getting close,” he grits out, and Prompto shivers with anticipation. “Close, Prompto, if you wanna pull back, now’s the time--” but Prompto doesn’t want to pull back. He does adjust himself so he’s focused on the head of Gladio’s cock while his hand takes over the rest, because he doesn’t want to choke on a rush of Gladio’s come--and it was a good idea, because then Gladio’s come is filling up his mouth and he _still_ almost chokes at the thick bitter fluid that coats his tongue in bursts.

He manages to swallow it all, though, and looks up at a panting Gladio. Gladio’s eyes are closed, but he ruffles a hand lazily through Prompto’s hair. “Mmmmgood,” Gladio slurs out, and Prompto smiles and wipes at his wet chin before lying out next to Gladio.

They kiss, slow and deep, and Gladio doesn’t seem to care what Prompto tastes like right now. Prompto doesn’t care what Gladio tastes like, either, and there’s something kinda hot knowing that they’re mixing the tastes of each other’s come. 

“That was _awesome,"_ Prompto breathes as they pull back, and this time he manages to keep eye contact when Gladio looks at him fondly.

“You’re not so bad yourself,” he teases, and seems to enjoy the scoff Prompto makes. 

“I’d be up for doing this again sometime.” Prompto tries to keep his voice light and casual, but Gladio seems to catch the hint of anxiety in it. He kisses Prompto again.

“Sounds good to me.”

Then the distant sound of Noct and Ignis’s voices reach them and they’re scrambling to get their clothes on and pat their hair down as the voices draw closer, and by the time they’re all together again, Prompto and Gladio look good as new. 

_We’re going to do this again,_ Prompto thinks with a secret grin. _And this time, I’m gonna get more of that dick._


End file.
